This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-113660, filed Apr. 21, 1999, the entire contents of which are incorporated herein by reference.
This invention relates to a substrate-treating technique in the manufacturing process of a semiconductor device, and in particular, to a substrate-treating device and a substrate-treating method for effectively feeding a chemical to the surface of a substrate for the treatment thereof.
In the manufacturing process of a semiconductor device or a liquid display device, the surface of substrate is subjected to various treatments or workings, thereby ultimately forming a fine pattern to provide the device with a desired function. In order to perform such treatments of substrate, not only a dry process using a gas, but also a wet process using a chemical solution are widely employed. This wet process is employed for instance in a development treatment to be performed after the exposure of a photosensitive resist, in the working of an exposure chromium mask, in the removal of undesired organic substance that has been adhered onto a substrate, in the removal of a photosensitive resist pattern left remained after finishing an etching treatment, or in a metal-plating on the surface of a silicon wafer.
There are known, as a wet process, a dipping method wherein a substrate is dipped in a solution of chemicals (or a chemical liquid) and a paddling method wherein a substrate is treated by feeding a chemical liquid to the main surface of the substrate. Since the dipping method is accompanied with problems that a large quantity of chemicals is required and the substrate may be contaminated through the reverse side thereof, the paddling method is increasingly substituted for the dipping method.
According to the conventional paddling method, a chemical is fed to the surface of substrate from a chemical supply source which is disposed above the substrate while allowing the substrate to rotate, the back side thereof being fixed by means of a vacuum chuck. However, since the delivery pressure of the chemical liquid as well as the quantity per unit area of a chemical liquid to be fed to the central surface portion of substrate are caused to differ from those to be fed to the marginal surface portion of the substrate according to this conventional method, it is impossible to achieve a high working precision.
With a view to overcome this problem, Japanese Patent Unexamined Publication No. 7-36195 discloses a method wherein a chemical liquid is fed to the main surface of substrate while moving a chemical-feeding section from one side of the substrate to the other side thereof. By contrast to the aforementioned rotational paddling method, it is possible according to this method to minimize the aforementioned difference in delivery pressure and in quantity of chemicals to be fed per unit area of the substrate. This method is further modified as disclosed in Japanese Patent Unexamined Publication No. 8-31729.
Namely, Japanese Patent Unexamined Publication No. 8-31729 describes a technique wherein the chemical-feeding section is provided at a lower portion thereof with a slit-like discharge port which is extended orthogonal to the moving direction of the chemical-feeding section and has the same width as that of the substrate to be treated, thereby enabling a chemical to be fed perpendicular to the main surface of the substrate from the discharge port. However, this raises another problem that since the liquid is discharged perpendicularly from the slit-like discharge port and strongly impinges against the surface of substrate, a turbulent flow is caused to generate on the surface of the substrate. Further, as a result of this turbulent flow, a fresh chemical is caused to mix with a reaction product, thereby non-uniformly lowering the concentration of the chemical and hence, giving rise to a non-uniform processing.
Japanese Patent Unexamined Publication No. 8-31729 also discloses that the direction of feeding a chemical liquid is inclined relative to the surface of substrate, and the chemical liquid is delivered from a port which is arranged approximately parallel with the surface of substrate. However, since the transport and feeding of a chemical liquid is executed using a continuous tube with high pressure to feed into high flow-resistant tube, the solution is caused to be fed at a high pressure to the surface of substrate, thus causing a turbulent flow to be generated on the surface of the substrate.
According to the aforementioned methods, since a high feeding pressure is applied to the discharge port, even a slight difference in working precision of the discharge port would invite a difference in pressure as well as in flow rate, thus deteriorating the working precision of the substrate.
On the other hand, according to the techniques described in these publications, the moving speed of the chemical-feeding means is taken into account with regard to the forward portion in the moving direction of the chemical-feeding means so as not to allow the chemical liquid to get ahead of the chemical-feeding means. However, no consideration is taken into account with regard to the flowing of the chemical liquid toward the direction (chemicals-feeding direction) opposite to the moving direction of the chemical-feeding means. Therefore, according to the techniques of these publications, the chemicals supplied to the substrate are allowed to flow to the downstream side while being mixed with a reaction product. As a result, the reaction speed at the downstream side becomes slower, thus giving rise to a problem that the dimensional precision of worked substrate is deteriorated.
Further, Japanese Patent Unexamined Publication No. 10-223507 discloses a method wherein a chemical liquid is fed as shown in FIG. 5A from a discharge port via a transporting face arranged contiguous with the discharge port to the surface of substrate. According to this system, the angle for feeding a chemical liquid to the surface of substrate may be approximately perpendicular to the surface of substrate or slightly inclined to the surface of substrate. Although the discharge port portion according to this system is an open type, a chemical liquid is caused to be transported along the transporting face disposed contiguous with the discharge port, so that the feeding pressure of chemicals would not be weakened, thus causing a chemical liquid to be fed to the surface of substrate at a very high speed.
In FIG. 5A, the size of the arrows shown therein indicates the magnitude of the feeding speed of a chemical liquid. As shown herein, in this case also, a turbulent flow of the chemical liquid is caused to generate at the portion of substrate where the chemical liquid is fed, or a phenomenon wherein the chemical liquid is caused to flow in the feeding direction thereof, or a reaction product is caused to flow toward the downstream side would be generated. Due to these unstable factors, the working precision of substrate is caused to deteriorate even in this system.
As explained above, the conventional wet process is accompanied with a problem that since the pressure of feeding a chemical liquid to the main surface of substrate is high, a turbulent flow of the chemical liquid is caused to generate on the surface of the substrate, thereby giving rise to the deterioration of working precision of the substrate.
Therefore, the object of the present invention is to provide a substrate-treating device which is capable of extremely lowering the velocity and feeding pressure of a chemical liquid on the occasion of feeding the chemical liquid to a substrate to be treated (hereinafter, referred to simply as a substrate), thereby enabling the working precision of the substrate to be improved.
Another object of the present invention is to provide a method of treating a substrate which is capable of extremely lowering the velocity and feeding pressure of a chemical liquid on the occasion of feeding the chemical liquid to a substrate to be treated, thereby enabling the working precision of the substrate to be improved.
Namely, according to this invention, there is provided a substrate-treating device comprising a substrate holder for approximately horizontally holding the substrate; a chemical liquid feeder having a chemical liquid delivery port for discharging a chemical liquid from a chemical liquid tank; a chemical liquid supplier disposed below the chemical liquid delivery port of the chemical liquid feeder and away from the chemical liquid delivery port, and having a chemical liquid-transporting face disposed parallel with or inclined to a main surface of the substrate for lowering the flowing velocity and pressure of the chemical liquid before feeding the chemical liquid discharged from the chemical liquid delivery port and flowing over the chemical liquid-transporting face to the main surface of the substrate; and moving mechanism for moving the chemical liquid supplier in relative to the substrate, wherein a relative moving speed between the substrate and the chemical liquid supplier is substantially the same with a velocity of the chemical liquid being fed from the chemical liquid supplier to the substrate; and a relative speed between the chemical liquid being fed from the chemical liquid supplier to the substrate and the substrate is substantially zero.
According to this invention, there is further provided a substrate-treating method, which comprises the steps of; discharging a chemical liquid from a chemical liquid feeder to a chemical liquid-transporting face of a chemical liquid supplier, the chemical liquid-transporting face being disposed parallel with or inclined to a main surface of the substrate which is held in an approximately horizontal state; and moving the chemical liquid supplier in relative to the substrate while allowing the chemical liquid discharged from the chemical liquid feeder to flow over the chemical liquid-transporting face; thereby enabling the chemical liquid discharged from the chemical liquid feeder and flowing over the chemical liquid-transporting face to be fed to an entire main surface of the substrate in state where the feeding velocity and pressure of the chemical liquid are reduced due to the relative movement between the chemical liquid supplier and the substrate, and a relative moving speed between the substrate and the chemical liquid supplier is substantially the same with a velocity of the chemical liquid being fed from the chemical liquid supplier to the substrate; and a relative speed between the chemical liquid being fed from the chemical liquid supplier to the substrate and the substrate is substantially zero.
According to this invention, there is further provided a substrate-treating method, which comprises the steps of; discharging a chemical liquid from a chemical liquid feeder to a chemical liquid-transporting face of a chemical liquid supplier, the chemical liquid-transporting face being disposed parallel with or inclined to a main surface of the substrate which is held in an approximately horizontal state, and the chemical liquid feeder having at least a couple of chemical liquid delivery ports which are mutually positioned in point symmetry with respect to the center of the substrate; and rotationally driving at least one of the substrate and the chemical liquid feeder during a moment when the chemical liquid discharged from the chemical liquid feeder is allowed to flow over the chemical liquid-transporting face in a manner where a surface of the chemical liquid is opened to ambient atmosphere; thereby enabling the chemical liquid discharged from the chemical liquid feeder and flowing over the chemical liquid-transporting face to be fed to an entire main surface of the substrate in state where the feeding velocity and pressure of the chemical liquid are reduced due to the rotational driving of at least one of the substrate and the chemical liquid feeder, and a relative moving speed between the substrate and the chemical liquid supplier is substantially the same with a velocity of the chemical liquid being fed from the chemical liquid supplier to the substrate; and a relative speed between the chemical liquid being fed from the chemical liquid supplier to the substrate and the substrate is substantially zero.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.